// Copyright (c) Hercules Dev Team, licensed under GNU GPL.
// See the LICENSE file
// Portions Copyright (c) Athena Dev Teams

#define HERCULES_CORE

#include "geoip.h"

#include <errno.h>
#include <stdio.h>
#include <sys/stat.h> // for stat/lstat/fstat - [Dekamaster/Ultimate GM Tool]

#include "../common/cbasetypes.h"
#include "../common/malloc.h"
#include "../common/showmsg.h"

struct s_geoip geoip_data;

struct geoip_interface geoip_s;

/* [Dekamaster/Nightroad] */
#define GEOIP_MAX_COUNTRIES 255
#define GEOIP_STRUCTURE_INFO_MAX_SIZE 20
#define GEOIP_COUNTRY_BEGIN 16776960

const char * geoip_countryname[GEOIP_MAX_COUNTRIES] = {"Unknown","Asia/Pacific Region","Europe","Andorra","United Arab Emirates","Afghanistan","Antigua and Barbuda","Anguilla","Albania","Armenia","Netherlands Antilles",
		"Angola","Antarctica","Argentina","American Samoa","Austria","Australia","Aruba","Azerbaijan","Bosnia and Herzegovina","Barbados",
		"Bangladesh","Belgium","Burkina Faso","Bulgaria","Bahrain","Burundi","Benin","Bermuda","Brunei Darussalam","Bolivia",
		"Brazil","Bahamas","Bhutan","Bouvet Island","Botswana","Belarus","Belize","Canada","Cocos (Keeling) Islands","Congo, The Democratic Republic of the",
		"Central African Republic","Congo","Switzerland","Cote D'Ivoire","Cook Islands","Chile","Cameroon","China","Colombia","Costa Rica",
		"Cuba","Cape Verde","Christmas Island","Cyprus","Czech Republic","Germany","Djibouti","Denmark","Dominica","Dominican Republic",
		"Algeria","Ecuador","Estonia","Egypt","Western Sahara","Eritrea","Spain","Ethiopia","Finland","Fiji",
		"Falkland Islands (Malvinas)","Micronesia, Federated States of","Faroe Islands","France","France, Metropolitan","Gabon","United Kingdom","Grenada","Georgia","French Guiana",
		"Ghana","Gibraltar","Greenland","Gambia","Guinea","Guadeloupe","Equatorial Guinea","Greece","South Georgia and the South Sandwich Islands","Guatemala",
		"Guam","Guinea-Bissau","Guyana","Hong Kong","Heard Island and McDonald Islands","Honduras","Croatia","Haiti","Hungary","Indonesia",
		"Ireland","Israel","India","British Indian Ocean Territory","Iraq","Iran, Islamic Republic of","Iceland","Italy","Jamaica","Jordan",
		"Japan","Kenya","Kyrgyzstan","Cambodia","Kiribati","Comoros","Saint Kitts and Nevis","Korea, Democratic People's Republic of","Korea, Republic of","Kuwait",
		"Cayman Islands","Kazakhstan","Lao People's Democratic Republic","Lebanon","Saint Lucia","Liechtenstein","Sri Lanka","Liberia","Lesotho","Lithuania",
		"Luxembourg","Latvia","Libyan Arab Jamahiriya","Morocco","Monaco","Moldova, Republic of","Madagascar","Marshall Islands","Macedonia","Mali",
		"Myanmar","Mongolia","Macau","Northern Mariana Islands","Martinique","Mauritania","Montserrat","Malta","Mauritius","Maldives",
		"Malawi","Mexico","Malaysia","Mozambique","Namibia","New Caledonia","Niger","Norfolk Island","Nigeria","Nicaragua",
		"Netherlands","Norway","Nepal","Nauru","Niue","New Zealand","Oman","Panama","Peru","French Polynesia",
		"Papua New Guinea","Philippines","Pakistan","Poland","Saint Pierre and Miquelon","Pitcairn Islands","Puerto Rico","Palestinian Territory","Portugal","Palau",
		"Paraguay","Qatar","Reunion","Romania","Russian Federation","Rwanda","Saudi Arabia","Solomon Islands","Seychelles","Sudan",
		"Sweden","Singapore","Saint Helena","Slovenia","Svalbard and Jan Mayen","Slovakia","Sierra Leone","San Marino","Senegal","Somalia","Suriname",
		"Sao Tome and Principe","El Salvador","Syrian Arab Republic","Swaziland","Turks and Caicos Islands","Chad","French Southern Territories","Togo","Thailand",
		"Tajikistan","Tokelau","Turkmenistan","Tunisia","Tonga","Timor-Leste","Turkey","Trinidad and Tobago","Tuvalu","Taiwan",
		"Tanzania, United Republic of","Ukraine","Uganda","United States Minor Outlying Islands","United States","Uruguay","Uzbekistan","Holy See (Vatican City State)","Saint Vincent and the Grenadines","Venezuela",
		"Virgin Islands, British","Virgin Islands, U.S.","Vietnam","Vanuatu","Wallis and Futuna","Samoa","Yemen","Mayotte","Serbia","South Africa",
		"Zambia","Montenegro","Zimbabwe","Anonymous Proxy","Satellite Provider","Other","Aland Islands","Guernsey","Isle of Man","Jersey",
		"Saint Barthelemy", "Saint Martin", "Bonaire, Saint Eustatius and Saba", "South Sudan"};

/* [Dekamaster/Nightroad] */
/* WHY NOT A DBMAP: There are millions of entries in GeoIP and it has its own algorithm to go quickly through them, a DBMap wouldn't be efficient */
const char* geoip_getcountry(uint32 ipnum)
{
	int depth;
	unsigned int x;
	const unsigned char *buf;
	unsigned int offset = 0;

	if( geoip->data->active == false )
		return geoip_countryname[0];

	for (depth = 31; depth >= 0; depth--) {
		buf = geoip->data->cache + (long)6 *offset;
		if (ipnum & (1 << depth)) {
			/* Take the right-hand branch */
			x =   (buf[3*1 + 0] << (0*8))
				+ (buf[3*1 + 1] << (1*8))
				+ (buf[3*1 + 2] << (2*8));
		} else {
			/* Take the left-hand branch */
			x =   (buf[3*0 + 0] << (0*8))
				+ (buf[3*0 + 1] << (1*8))
				+ (buf[3*0 + 2] << (2*8));
		}
		if (x >= GEOIP_COUNTRY_BEGIN) {
			x = x-GEOIP_COUNTRY_BEGIN;

			if( x > GEOIP_MAX_COUNTRIES )
				return geoip_countryname[0];

			return geoip_countryname[x];
		}
		offset = x;
	}
	ShowError("geoip_getcountry(): Error traversing database for ipnum %d\n", ipnum);
	ShowWarning("geoip_getcountry(): Possible database corruption!\n");

	return geoip_countryname[0];
}

/**
 * Disables GeoIP
 * frees geoip.cache
 **/
void geoip_final(bool shutdown)
{
	if (geoip->data->cache) {
		aFree(geoip->data->cache);
		geoip->data->cache = NULL;
	}

	if (geoip->data->active) {
		if (!shutdown)
			ShowStatus("GeoIP "CL_RED"disabled"CL_RESET".\n");
		geoip->data->active = false;
	}
}

/**
 * Reads GeoIP database and stores it into memory
 * geoip.cache should be freed after use!
 * http://dev.maxmind.com/geoip/legacy/geolite/
 **/
void geoip_init(void)
{
	int i, fno;
	char db_type = 1;
	unsigned char delim[3];
	struct stat bufa;
	FILE *db;

	geoip->data->active = true;

	db = fopen("./db/GeoIP.dat","rb");
	if (db == NULL) {
		ShowError("geoip_readdb: Error reading GeoIP.dat!\n");
		geoip->final(false);
		return;
	}
	fno = fileno(db);
	if (fstat(fno, &bufa) < 0) {
		ShowError("geoip_readdb: Error stating GeoIP.dat! Error %d\n", errno);
		geoip->final(false);
		return;
	}
	geoip->data->cache = aMalloc( (sizeof(geoip->data->cache) * bufa.st_size) );
	if (fread(geoip->data->cache, sizeof(unsigned char), bufa.st_size, db) != bufa.st_size) {
		ShowError("geoip_cache: Couldn't read all elements!\n");
		fclose(db);
		geoip->final(false);
		return;
	}

	// Search database type
	fseek(db, -3l, SEEK_END);
	for (i = 0; i < GEOIP_STRUCTURE_INFO_MAX_SIZE; i++) {
		if (fread(delim, sizeof(delim[0]), 3, db) != 3) {
			db_type = 0;
			break;
		}
		if (delim[0] == 255 && delim[1] == 255 && delim[2] == 255) {
			if (fread(&db_type, sizeof(db_type), 1, db) != 1) {
				db_type = 0;
			}
			break;
		} else {
			fseek(db, -4l, SEEK_CUR);
		}
	}

	fclose(db);

	if (db_type != 1) {
		if (db_type)
			ShowError("geoip_init(): Database type is not supported %d!\n", db_type);
		else
			ShowError("geoip_init(): GeoIP is corrupted!\n");

		geoip->final(false);
		return;
	}
	ShowStatus("Finished Reading "CL_GREEN"GeoIP"CL_RESET" Database.\n");
}

void geoip_defaults(void)
{
	geoip = &geoip_s;

	geoip->data = &geoip_data;

	geoip->getcountry = geoip_getcountry;
	geoip->final = geoip_final;
	geoip->init = geoip_init;
}
